LEESON NEMA 4X SCR Control: 174903.00 (Obsolete) - Manual (Page 10)

START-UP PROCEDURE
9
The trimpot adjustments, MIN, MAX, I.R. COMP, and CUR LIM are checked at the factory using
a typical motor at 240 VAC input. Use the TRIMPOT CHART on page 11 to preset the trimpots
for the proper setting for your application. The remaining trimpot - ACCEL, is a variable
acceleration and should be set for your particular application.
The trimpot chart is approximate. The chart is valid when using the speedpot or a 0-10/12 VDC
input signal to set speed.
These adjustments are permanent; periodic readjustment is normally not needed. Operation
of the control beyond ±10% of normal line voltage could result in readjustments.
ADJUSTMENTS
WARNING:
ALL POWER MUST BE TURNED OFF BEFORE PROCEEDING !!!
1. Recheck all wiring. Accidental grounds, loose or pinched wires on armature or speedpot
wires may damage the control when power is applied.
2. Check to see that incoming service is of correct voltage.
3. Turn speedpot to zero (fully CCW).
4. Turn power on and advance speedpot while observing motor.
WARNING: POWER MUST BE OFF BEFORE STEP 5 CAN BE ACCOMPLISHED!
5. If motor rotation is incorrect, turn power off at external disconnect and reverse +ARM and
-ARM connections.
6. Check for satisfactory operation throughout the speed range.
7. If operation is satisfactory, no readjustments are needed.
8. If instability or surging is observed, or if maximum speed is higher than desired, proceed to
“TRIMPOT ADJUSTMENT” on pages 10 and 11.
9. For other problems, consult page 14, “IN CASE OF DIFFICULTY”.